API: Raise on ``iloc`` indexing with a mask boolean that is not an ndarray (GH3631_)

     PTF

TST: added @snth test harness

DOC: doc updates for release notes,indxing.rst and v0.11.1
CLN: added NotImplementedError when trying to iloc with a mask that has an integer index

     (rather than ValueError)
Merge pull request #3635 from jreback/iloc_mask

API: Raise on iloc indexing with a non-integer based boolean mask (GH3631)